Definitely, positively get a nice optical mouse with a right-click button. There’s not a single part of the MacOS, or any app that it can run, that doesn’t instantly recognize and respond properly to the right-click. I am a Mac person who has never owned a PC and I’ve probably spent no more than 60 hours grand total using a PC, but right-click is one nice thing the PC side came up with that the Mac has begrudgingly copied.
BootCamp: do you have an XP SP2 (or Vista, of course) installer? Nothing pre-SP2 will work. Although you can “slipstream” a homemade XP installer if you don’t have SP2 on CD.
Text files: Once upon a time in a long-ago era, it was an issue that Mac plain-text files used only a carriage return to mark end-of-line. Either Windows used carriage return + line feed and Unix used only line feed, or vice versa, I don’t recall which. It hasn’t been an issue in so long that I’m thinking either the OS itself or all modern apps that have anything to do with text files just adjust for end-of-line codes on the fly. I could be wrong. If you want to post a plain-text file (with hard returns of course) from Windows somewhere that I can download it, I will report back to you on whether or not it’s still an issue. It’s a fixable one even if it is an issue, btw: free Mac software such as TextWrangler will replace line feeds with carriage returns, and do 'em in batches if it comes to that. I really don’t think it’s an issue though.
MP3: common file format, no issues.
== Stuff you didn’t ask ==
Video formats. Got a lot of .avi or .wmv files, perhaps a few .flv files from YouTube, an .mpg or two, some .mov files as well, maybe? The MacOS does not ship with a comprehensive supply of video codecs and format-handlers. A great many are free and once installed will let you play your video files, but initially you may find it a hassle to chase them down, download them, and install them.
Access database files?: There ain’t no Access for MacOS. You can get a partial rescue from the Base module in OpenOffice or NeoOffice (the former being an X11 app, the latter being a Java version of same). But any vBasic-powered stuff that may have been written into your Access file will not perform under OpenOffice/NeoOffice. Mac users use FileMaker Pro. If you do database you’ll have to learn it. (It’s nice, but it’s not an Access clone. You’ll have to start over)
Windows don’t maximize in the MS-Windows sense of the word. They just zoom to a size sufficient to handle window contents. For some reason this seems to drive lots of former Windows users nuts at first. Mac apps don’t have an “application window” behind the document window, so not-maximized means being able to see other apps’ windows and switch to them by clicking on their windows.
Also because Mac apps don’t have application windows, closing the last close button you see onscreen doesn’t quit the app. That’s not a problem. You can have 40 or 60 apps running concurrently and it won’t hurt a thing if they don’t have processes going on; they won’t request processor cycles if you’ve closed all their windows, and their RAM will get paged out. But again it bothers some Windows switchers.
Single-clicking an icon and hitting return doesn’t launch or open the document or app. MacOS thinks you want to rename the file when you do that. If you want to launch/open it, either double-click it or single-click it and ⌘-down-arrow it to launch/open.
BootCamping: MacOS doesn’t natively let you write to NTFS disks (although it can deal with them read-only), and XP & Vista don’t comprehend HFS+ (the MacOS native disk format). If you want your Windows apps to have access to files stored in Mac-land, shell out for MacDrive. On the Mac side, install the free MacFUSE file system architecture (a user-space file system protocol) + the associated NTFS-3G which gives you full read-write support for NTFS disks. I know you can do FAT-32 for your Windows environment, but Windows really prefers NTFS, doesn’t it?
Parallels: Strongly consider Parallels even though it is not free. Instead of having a choice between Windows OR MacOS, run both at the same time. Also run Windows98 and Ubuntu and any other PC OS. My GF is totally a Windows-only person. She’s using a Mac Mini, never sees the MacOS at all, runs her entire Sony VAIO ported environment (Parallels lets you make a virtual machine of your existing Windows box, way cool) full-screen and forgets it’s just a virtual environment. You can also integrate them (right-click a file in Windows and you have the option of opening it in an appropriate Mac app, and vice versa; or hide Windows’ Desktop and just keep the Start Menu and your individual Windows document windows and they get treated like Mac apps’ windows.